Thread pull-off for sewing machines



J. w. CONNORS THREAD PULL-OFF FOR SEWING MACHINES June 22,1926. I 1,589,629

Fi led Dec. 26, 1924 2 Sheets-Sheet 1 lnvenTor. \John W.C0nnors Afl'ys.

June 22 1926. 1,589,629

' J. W. CONNORS THREAD PULL-OFF FOR SEWING MACHINES Filed Dec. 26, 2 2 Sheets-Sheet Fig.8. Fig.4. is 26 \John W. Connors 39 by/MWkMm/Z I that is situated beneath the bed frame.

Patented June 22, 1936.

UNITED STATES 1,589,629 PATENT OFFICE.

. JOHN W. CONNORS, OF DEDHAM, MASSAJGHUSETTS, ASSIGNOR TO THE REECE BUTTON HOLE MACHINE COMPANY, 013 BOSTON, MASSACHUSETTS, A CORPORATION OF SMAINE.

'rnanazo Punt-or]? FOR SEWING MACHINE-S.

Application filed December 26, 1924.. Serial No. 758,104.

This invention relates to two-thread buttonhole sewing machines of that familiar type in which the under thread handling mechanism is mounted on a rotary turret An exemplification of sewing machines of this type will be found in United States Patents No. 1,188,942, June 27th, 1916, No. 1,338,237 3, April 27 th, 1920, and No. 1,406,742, February 14th, 1922.

Some buttonhole sewing machines of' the above-mentioned type are provided with means for cutting the under thread close to the work at the end of the stitching operations on a buttonhole and are also provided with means to pull off a length of under thread from the source of supply just before the under thread is cut in order to leave an end of sufiicient length to ensure the proper formation of the first stitch at the beginning of the next buttonhole;

The present invention relates particularly to the pull-off device for thus pulling off a length of under thread and is in the nature of an improvement on the illustrated in my Patent No. 1,535,399, dated April 28th, 1925.

One of the objects of the invention is to provide an improved pull-off which is more simple and involves the use of fewer parts than. the pull-off illustrated in the above-mentioned Patent No. 1,535,399.

In order to give an understanding of the invention I have illustrated in the drawings a selected embodiment thereof which will now be described after'which the novel features will be pointed out in the appended claims.

Fig. 1 is a side elevation of the turret carrying the under thread handling mechanism showing my improved pull-off device mounted thereon;

Fig. 2 1s a View of the turret looking from the opposite side fromthat shown in Fig. 1; f

' the usual swinging needle carrier 9 and the Fig. 3 is a side view of the turret; Figs. 4, and 5 are plan views of the turret showing the switch cam and its method carried and the looper derlve then moveof operation;

Fig. 6 is a fragmentary side elevation of the switch cam;

Figs. 7 and 8 are fragmentary sectional views showing switch cam and the tail of the actuator and illustrating the manner in which the switch cam operates;

Fig. 9 is a fragmentary view of the pull-0H device actuating lever and the switch cam also illustrating the. operation of the switch cam. Inasmuch as the present invention relates simply to the pull-olf for the under thread which is mounted on the turret I have confined the illustration in the present application largely to the turret, and have shown only so much of the sewing machine as necessary to'illustrate the invention.

It will be understood that the complete sewing machine is provided with a bed frame which supports the work-holding .means and is also provided with the usual tonhole in order to carry the stitching around the end of the buttonhole and it will be understood that in sewing machines of this class after the stitching has been completed on the buttonhole the turret is given a turning movement to return it to its normal ini tial position. f

The'turret 1 isprovided with the usual throat plate4which has a sewing opening 5 through which the upper needlereciprocates.

The under threadunanipulating mechanism comprises the'usual looper 6 and under needle 7 the looper 6 operating to take each loop of upper thread as it is thrown out by the upper needle and hold said loop spread while the under needle 7 carries the loop of under thread 8 through said loop of upper thread. The under'needle 7 is mounted in looper is carried by a rocking member 10 pivoted at 11 to the turret. Both the needle 16 for tensioning the under thread. Said tension device is herein shown as comprising t-wo tension disks 17, 18 between which the under thread passes, said disks being acted on by a suitable spring 19 which applies tension to the thread. The strength of the spring may be adjusted by the usual thumb nut 20.

The under thread 8 passes up through the hollow spindle 12 and out through a slot 21 therein, thence through the tension device 16 and through guide eyes 22, 23, 24 and thence to the needle, this being the usual manner of threading up the under thread.

The pull-off for the under thread is similar in construction to that illustrated in my above-mentioned Patent No. 1,535,399. It comprises a pull-off lever 25 pivoted at 26 to the turret and provided at its end with a finger 27 which operates directly underneath the throat plate 4: and between the lat ter and the loop'er. This pull-off is normally in the position shown in Fig. 4 and the pulling off of the under thread is se- 'cured by swinging said pull-off into the position shown in Fig. 5, this movement carrying the finger 27 from one side to the other of the sewing opening 5 in the throat plate.

In an effort to simplify the mechanism required for giving the pull-off its operative movement I have provided means whereby it derives such operative movement from the reverse turning movement which the turret has after the stitching on the buttonhole has been completed and while the turret is being turned to bring it from the position it occupied at the end of the sewing back to its initial position again.

When the sewing is being carried around the end of the buttonhole as the buttonhole is completed the turret is being turned in the direction of the arrow at in Fig. 4:. After the sewing has been completed and the stitch-forming mechanism has come to rest and while the work is being carried from stitching to buttonhole cutting position the turret is given a fevers-e turning movement in the direction of the arrow I) Fig. 5 to bring it to its normal position, this sequence of movement being involved in the regular cycle of operations in stitching a buttonhole.

I have provided herein novel means whereby the pull-off 25 is operated during the reverse turning movement of the turret after the stitching has been completed and as indicated in Fig. 5. This is herein accomplished by employing a switch cam 28 which is carried by the bed frame 3 and is arranged to be inoperative during the forward turning movement of the turret in the direction of the arrow a but which becomes operative to actuate the pull-off device during the reverse turning movement of the turret in the direction ofthe arrow 6.

Pivotally mounted on the turret at 29 is an actuating lever 30 which has an up-standing arm 31 that is received in a slot 32 formed in the pull-off lever 25. This actuating member 30 is formed with a tail or finger 33 which co-operates with the switch cam 28. This switch cam 28 is carried by a swinging arm or support 31 which is pivoted at 35 to the bed frame 3 and is provided with a cam face 36.

The pivoted support 34 is provided with an adjustable stop 37 adapted to rest on the portion 38 of the bed frame and said memher is yieldingly held in this position by means of a spring 39.

The parts are so adjusted that the flat horizontal portion of the switch cam is located above the path of movement of the tail 33 when the pull-off is in the position shown in Figs. 1 and 4, which is the position of the parts during the stitching operation.

The tail 33 is long enough to overlap the switch cam somewhat as clearly seen in Fig. 5 and hence when during the turning movement of the turret in the direction of the arrow a Fig. 4 at the time that the stitching on the button hole is being completed, said tail 33 will pass underneath the switch cam 28 and wipe past the downwardly curved portion 36 of said switch cam, the. latter and the arm 34 being raised by the tail to allow the latter to pass as shown in dotted lines Fig. 7. At the completion of the stitching on the buttonhole the turret has turned to bring the tail into the dotted line position 700 Fig. 4.. Vhile the work is being moved from stitching to button hole cutting position the turret is given a reverse turning movement in the direction of the arrow 6 in Fig. 5. During this reverse movement the tail of the 105 pull-off actuator 30 engages the cam face 36 of the switch cam and rides up the latter to the top of the switch cam as shown in Figs.

5 and 9.

During this operation the switch cam is 119 held from downward movement by engagement of the stop 37 with the part 38 and hence the engagement of the tail 33 with the cam portion 36 will turn the actuator 30 from the position shown in Fig. 1 to that 115 shown in Figs. 5 and 9. This turning movement operates through the arm 31 to swing the pull-off into the position shown in Fig. 5 thereby pulling off a length of under thread.

The operation of the pull-off device, therefore, involves merely the use of the switch cam which of itself is a comparatively simple structure.

The device also includes means for re 125 lieving the tension on the. under thread at the time that the pull ofi' operates. The mechanism for accomplishing this is similar to that illustrated in my above-mentioned Patent No. 1,535,399. The tension is released by means of a push pin 40 which is acted upon by a cam face 41 formed on a vertically sliding block 42. This block has a rod or pin 43 rising therefrom which is connected to a laterally-extending ear 44 formed on the swinging actuator 30. When the actuator 30 is swung upwardly by the cam face 86 thereby to give the pull-off finger its operative. movement such upward swinging movement of the actuator will raise the cam block 42 and cause the cam face 41 to actuate the push pin 40 thereby to relieve the tension on the under thread. This relieving of the tension is thus coincident with the pulling off of the under thread.

50 designates a return spring connected to the block 42 for the purpose of returning the parts to their normal positions.

I claim:

1. In a buttonhole sewing machine of the type having a rotary turret carrying the un der thread-manipulating mechanism, the combination with said turret, of a pull-off device mounted on the turret for pulling off a length of under thread, means on the turret to apply tension to theunder thread, and means actuated by the rotary movement of the turret to actuate the pull-ofi and simultaneously release the tension.

2. In a buttonhole sewing machine having a frame, a rotary turret and an under thread-manipulating mechanism mounted thereon, the combination with said turret, of a throat plate carried thereon, a'pull-otf member pivotally mounted on the turret to swing about a vertical axis, said pull-oif member having a slot, an actuating lever pivoted to the turret to swing about a horizontal axis and provided with an arm operating in the slot and a horizontally projecting tail or finger, and a member carried by the frame and with which said tail or finger engages during the rotary movement of the turret thereby to swing the actuating lever in a vertical plane and actuate the pull-0E device.

3. In a buttonhole sewing machine having a rotary turret and under thread-ma nipulating mechanism mounted thereon, the combination with said turret, of a throat plate carried thereby, under thread-manipu--- lating mechanism mounted on the turret and including a needle, a pull-off device mounted on the turret and engaging the under thread between the needle and the throat plate, means on the turret to apply tension to the under thread, and means operated by the rotary movement of the turret to simultaneously release the tension and actuate the pull-off. I

4. In a buttonhole sewing machine having a rotary turret on which under threadmanipulating mechanism is supported, the combination wit-h said turret, of a pull-off member pivotally mounted thereon, an actuating lever also pivotally mounted thereon to turn aboutan aXis at right angles to that of the pull-off member, said actuating lever being operatively connectedto the pull-off member, and means for actuating the lever by the turning movement of the turret.

5. In a buttonhole sewing machine having a rotary turret supporting under threadhandling mechanism, the combination with said turret,of a pull-01f member pivotally mounted on the turret to swing about a vertical axis, an actuating lever pivoted to the turret to turn about a horizontal, axis, said actuating lever being operatively connected to the pull-off member and having a horizontally-extending finger and a cam member with which the finger co-operates as the turret is turned to actuate the leverand therethrough the pull-oil device.

6. In a buttonhole sewing machine having a rotary turret carrying under threadmanipulating mechanism and which is given a forward rotation during the sewing around the end of the buttonhole and then a reverse rotation, the combination with said turret, of a pull-off device for the under thread pivoted to the turret to turn about a vertical axis, an actuating lever pivoted to the turret to turn about a horizontal axis, said lever being operatively connected to the pull-off member and provided with a tail, and a cam member co-operating with said tail which is inoperative during the forward rotation of the turret but is operative to actuate the actuating lever during the reverse rotation.

7. In a buttonhole sewing machine having a rotary turret carrying under thread-manipulating mechanism and which is given a forward rotation during the sewing around the end of the buttonhole and then a reverse rotation,-the combination with said turret, of a pull-off member for the under thread pivotally mounted on the turret, an actoating lever operatively connected to the pullofi' member and pivoted to the turret to turn about an axis at right angles to that of the pull-off member, said actuating lever having a tail or projection, and a mail member cooperating with said tail, said cam member being inoperative during the forward rotation of the turret but having operative en-. gagement with said tail thereby to actuate the lever during the reverse rotation of the turret.

8. In a buttonhole sewing machine having a rotary turret carrying under thread-manipulating mechanism and which is given a forward rotation during the sewing around the end of the buttonhole and then a reverse rotation, the combination with said turret, of a pull-off device for the under thread mounted on'the turret, an actuating lever a reverse rotation, the combination with said turret, of a pull-oil device for the under thread mounted on the turret, an actuating lever pivoted to the turret, for operating the pull-oil device, a pivoted cam member with which the lever has engagement during the turning of the turret, a tension device on the turret to apply tension to the under thread, and means to release the tension by the movement of the actuating lever.

In testimony whereof, I have signed my name to this specification.

JOHN W. CONNORS.

' 1 s Patent No. app icainon of John W. C0 t lf 1read Pull-Offs fol kewlng JVIacI printed specification requiring correction a age 8, lines 110 and 111, misspelled worc ct read actuating; a

' cam; and that the said Letters Pa 1211; the same may conform to 15 b anted June 22, 1926, nnors, cf Dedhaln, i 

